1. Field
The following description relates to a hall sensor device and an optical image stabilization device operable to cancel a direct current (DC) offset.
2. Description of Related Art
Recently-released mobile devices have been equipped with camera modules, and as levels of performance of mobile devices have increased, mobile devices in which high performance camera modules, having levels of resolution from millions of pixels to tens of millions of pixels or more, are mounted, have been released onto the market. However, even though high-pixel camera modules are required in mobile devices, an amount of space available for camera modules is inevitably limited, due to inherent limitations of available space within mobile devices. As a result, a small lens aperture, a small image pixel size, and the like, in addition to factors such as subtle motion due to external vibrations, hand-shake, and the like, may contribute to image deterioration when an image is captured.
In order to suppress image deterioration caused by the above-mentioned subtle vibrations and obtain a clearer image, various image correction methods have been developed. For example, a method employing an optical image stabilization (OIS) device to provide an optical hand-shake correction function has been developed. The OIS device may use a hall sensor to detect positions of a lens on an X axis and a Y axis, and may calculate a hand-shake component detected by a gyro sensor and position information of the lens on the X axis and the Y axis to drive the positioning of the lens.
In general, user hand-shake is generated in a frequency range from less than 1 Hz to a few tens of Hz. As a result, as described in Japanese Patent Laid-Open Publication No. 2007-88829, the detection signal from the gyro sensor is quantized prior to passing through a high pass filter (HPF), and thus the DC offset, drift components, and the like, included in the detection signal, may be canceled.
However, the hand-shake frequency between 1 Hz and a few tens of Hz may be included in an output signal of the hall sensor and a frequency or a level of the output signal of the hall sensor may be low. Therefore, a direct current (DC) offset may occur when the output signal is amplified, thereby causing malfunctioning of the OIS device.
In addition, in a case in which the optical image stabilization device is operated with a low noise level at the time of canceling the DC offset, the optical image stabilization device may correctly perform the hand-shake correction function.